说明：  根据标准MODBUS协议，c51编写的modbus通信，支持01H,02H,03H,04H,05H,06H,0FH,10H功能码，已在产品上使用
(According to the standard MODBUS protocol, c51 prepared Modbus communications, to support the 01H, 02H, 03H, 04H, 05H, 06H, 0FH, 10H function code has been used in products)